According to the podcast Mike posted (thanks again!) it sounds like this time frame estimate is right. They talked about needing people for the holidays and that means putting instructors on the line, which in turn slows down the hiring.

Mr. Hornibrook also mentioned that the hiring numbers for next year are expected to be less than this year (which was around 200), but that that number is obviously a moving target and could (and probably will) change. He also talked about the guys who are planning to retire this year need to tell the company by Halloween, so they'll have a better estimate for numbers at that point as well.